3D Sketch Stroke Segmentation and Fitting in Virtual Reality

In this paper we present a method which tries to automatically represent the designer’s intention while sketching threedimensional curves in a Virtual Reality environment. We translate conceptual sketch strokes into a suitable B-spline representation with a three step method. Firstly a data filter is used to eliminate redundancy and noise in ‘pen’ position recorded by the 3D tracking system. Secondly an knowledge based algorithm tries to interpret user’s intention, according to direction, speed and curvature of the virtual pen segmenting the stroke into two types of curves joined respectively with C and G continuity. Lastly an algorithm translates the points of each segmented sketch stroke into a cubic B-spline with adaptive approximation. This method, which has been integrated in our Virtual Reality sketching system, is illustrated and tested with various types of sketches.